BIO 269 QUESTIONS AND ANSWERS LATEST UPDATE 100%
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Pulmonary Circuit
Blood to and from the lungs.
Systemic Circuit
Heart to tissues
Atria
Receiving chambers of the heart
Right atria
Receives blood returning from the systemic circuit
Left atria
Receives blood returning from the pulmonary circuit
Ventricles
Pumping chambers of the heart
Right ventricle
Pumps blood into the pulmonary circuit
Left ventricle
Pumps blood into the systemic circuit
Pericardium
Protective fluid filled sac surrounding the heart.
Heart Wall
Epicardium: most superficial
Myocardium: thickest wall
Endocardium: epithelial lining
Atrioventricular Valves (AV)
Prevent back flow of blood into the atria when the ventricles contract
Tricuspid Valve
right AV valve
Bicuspid Valve
left AV valve
Semilunar Valve (SL)
Prevents black flow of blood into the ventricle
Pulmonary Valve
right SL valve
Aortic Valve
left SL valve
Coronary Circulation
-Coronary arteries arise from the base of the aorta
-Venous blood empties into the right atrium
Angina pectoris
TEMPORARY blockage of coronary arterial circulation (halt in blood delivery)
Myocardial Infarction (heart attack)
PROLONGED coronary blockage that leads to cell death and a build up of scar tissue
that doesn't allow the heart to contract
, Conductive Pathway
-SA Node
-AV Node
-AV Bundle
-Bundle Branches
-Purkinje Fibers
What chemical accelerates heart rate
Norepinephrine (cardiac nerves)
What chemical decelerates heart rate
Acetylcholine (vagus nerve)
What is pacemaker potential?
Slow depolarization from opening of NA+ channels and closing of K+ channels
(membrane potential is never a flat line)
Pacemaker depolarization
Pacemaker potential reaches the threshold and there is a large influx of Ca2+ though
the Ca2+ channel
Pacemaker repolarization
Ca2+ channels close and K+ channels open. K+ efflux allows the membrane potential
to go back to it's most negative voltage
Cardiac myocyte rapid depolarization
Due to Na+ inflow when the Na+ channels open
Cardiac myocyte plateau (maintained depolarization)
Due to Ca2+ inflow and K+ outflow when SOME k+ channels open
Cardiac myocyte repolarization
Due to clousure of Ca2+ channels and k+ outflow when ALL the K+ channels open
What causes the refractory period?
Sodium channels are inactive and sodium cannot enter to depolarize
Why is the refractory period important?
It prevents the heart from beating too fast
ECG Step 1 (Pwave)
Atrial depolarization allows the atrium to contract
ECG Step 2 (AV Node)
Impulse is delayed at the atrioventricular node
ECG Step 3 (QRS Complex)
Ventricular depolarization begins
ECG Step 4
Ventricular depolarization finishes and causes a slight plateau
ECG Step 5 (Twave)
Ventricular repolarization begins at apex
ECG Step 6
Ventricular repolarization is complete
Normal ECG
Arrhythmia: Junction Rhythm
-AV node takes over role of damaged SA node
-No p wave
-Slower heart rate (40-60bpm)
CORRECT A+ GRADED. Buy Quality Materials!
Pulmonary Circuit
Blood to and from the lungs.
Systemic Circuit
Heart to tissues
Atria
Receiving chambers of the heart
Right atria
Receives blood returning from the systemic circuit
Left atria
Receives blood returning from the pulmonary circuit
Ventricles
Pumping chambers of the heart
Right ventricle
Pumps blood into the pulmonary circuit
Left ventricle
Pumps blood into the systemic circuit
Pericardium
Protective fluid filled sac surrounding the heart.
Heart Wall
Epicardium: most superficial
Myocardium: thickest wall
Endocardium: epithelial lining
Atrioventricular Valves (AV)
Prevent back flow of blood into the atria when the ventricles contract
Tricuspid Valve
right AV valve
Bicuspid Valve
left AV valve
Semilunar Valve (SL)
Prevents black flow of blood into the ventricle
Pulmonary Valve
right SL valve
Aortic Valve
left SL valve
Coronary Circulation
-Coronary arteries arise from the base of the aorta
-Venous blood empties into the right atrium
Angina pectoris
TEMPORARY blockage of coronary arterial circulation (halt in blood delivery)
Myocardial Infarction (heart attack)
PROLONGED coronary blockage that leads to cell death and a build up of scar tissue
that doesn't allow the heart to contract
, Conductive Pathway
-SA Node
-AV Node
-AV Bundle
-Bundle Branches
-Purkinje Fibers
What chemical accelerates heart rate
Norepinephrine (cardiac nerves)
What chemical decelerates heart rate
Acetylcholine (vagus nerve)
What is pacemaker potential?
Slow depolarization from opening of NA+ channels and closing of K+ channels
(membrane potential is never a flat line)
Pacemaker depolarization
Pacemaker potential reaches the threshold and there is a large influx of Ca2+ though
the Ca2+ channel
Pacemaker repolarization
Ca2+ channels close and K+ channels open. K+ efflux allows the membrane potential
to go back to it's most negative voltage
Cardiac myocyte rapid depolarization
Due to Na+ inflow when the Na+ channels open
Cardiac myocyte plateau (maintained depolarization)
Due to Ca2+ inflow and K+ outflow when SOME k+ channels open
Cardiac myocyte repolarization
Due to clousure of Ca2+ channels and k+ outflow when ALL the K+ channels open
What causes the refractory period?
Sodium channels are inactive and sodium cannot enter to depolarize
Why is the refractory period important?
It prevents the heart from beating too fast
ECG Step 1 (Pwave)
Atrial depolarization allows the atrium to contract
ECG Step 2 (AV Node)
Impulse is delayed at the atrioventricular node
ECG Step 3 (QRS Complex)
Ventricular depolarization begins
ECG Step 4
Ventricular depolarization finishes and causes a slight plateau
ECG Step 5 (Twave)
Ventricular repolarization begins at apex
ECG Step 6
Ventricular repolarization is complete
Normal ECG
Arrhythmia: Junction Rhythm
-AV node takes over role of damaged SA node
-No p wave
-Slower heart rate (40-60bpm)
